// Copyright (c) 2018 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#include "gtest/gtest.h"
#include "leveldb/env.h"
#include "port/port.h"
#include "util/env_windows_test_helper.h"
#include "util/testutil.h"

namespace leveldb
{

    static const int kMMapLimit = 4;

    class EnvWindowsTest : public testing::Test
    {
    public:
        static void SetFileLimits(int mmap_limit)
        {
            EnvWindowsTestHelper::SetReadOnlyMMapLimit(mmap_limit);
        }

        EnvWindowsTest() : env_(Env::Default()) {}

        Env *env_;
    };

    TEST_F(EnvWindowsTest, TestOpenOnRead)
    {
        // Write some test data to a single file that will be opened |n| times.
        std::string test_dir;
        ASSERT_LEVELDB_OK(env_->GetTestDirectory(&test_dir));
        std::string test_file = test_dir + "/open_on_read.txt";

        FILE *f = std::fopen(test_file.c_str(), "w");
        ASSERT_TRUE(f != nullptr);
        const char kFileData[] = "abcdefghijklmnopqrstuvwxyz";
        fputs(kFileData, f);
        std::fclose(f);

        // Open test file some number above the sum of the two limits to force
        // leveldb::WindowsEnv to switch from mapping the file into memory
        // to basic file reading.
        const int kNumFiles = kMMapLimit + 5;
        leveldb::RandomAccessFile *files[kNumFiles] = {0};
        for (int i = 0; i < kNumFiles; i++)
        {
            ASSERT_LEVELDB_OK(env_->NewRandomAccessFile(test_file, &files[i]));
        }
        char scratch;
        Slice read_result;
        for (int i = 0; i < kNumFiles; i++)
        {
            ASSERT_LEVELDB_OK(files[i]->Read(i, 1, &read_result, &scratch));
            ASSERT_EQ(kFileData[i], read_result[0]);
        }
        for (int i = 0; i < kNumFiles; i++)
        {
            delete files[i];
        }
        ASSERT_LEVELDB_OK(env_->RemoveFile(test_file));
    }

} // namespace leveldb

int main(int argc, char **argv)
{
    // All tests currently run with the same read-only file limits.
    leveldb::EnvWindowsTest::SetFileLimits(leveldb::kMMapLimit);
    testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}
